package com.henu.util;import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;/*** 缓存管理类* * @author Administrator* */
public class CacheMgr {private static Map cacheMap = new HashMap();private static Map cacheConfMap = new HashMap();private static CacheMgr cm = null;// 构造方法private CacheMgr() {}public static CacheMgr getInstance() {if (cm == null) {cm = new CacheMgr();Thread t = new ClearCache();t.start();}return cm;}/*** 增加缓存* * @param key* @param value* @param ccm*            缓存对象* @return*/public boolean addCache(Object key, Object value, CacheConfModel ccm) {System.out.println("开始增加缓存－－－－－－－－－－－－－");boolean flag = false;try {cacheMap.put(key, value);cacheConfMap.put(key, ccm);System.out.println("增加缓存结束－－－－－－－－－－－－－");System.out.println("now addcache==" + cacheMap.size());flag = true;} catch (Exception e) {e.printStackTrace();}return flag;}/*** 获取缓存实体*/public Object getValue(String key) {Object ob = cacheMap.get(key);if (ob != null) {return ob;} else {return null;}}/*** 获取缓存数据的数量* * @return*/public int getSize() {return cacheMap.size();}/*** 删除缓存* * @param key* @return*/public boolean removeCache(Object key) {boolean flag = false;try {cacheMap.remove(key);cacheConfMap.remove(key);flag = true;} catch (Exception e) {e.printStackTrace();}return flag;}/*** 清除缓存的类 继承Thread线程类*/private static class ClearCache extends Thread {public void run() {while (true) {Set tempSet = new HashSet();Set set = cacheConfMap.keySet();Iterator it = set.iterator();while (it.hasNext()) {Object key = it.next();CacheConfModel ccm = (CacheConfModel) cacheConfMap.get(key);// 比较是否需要清除if (!ccm.isForever()) {if ((new Date().getTime() - ccm.getBeginTime()) >= ccm.getDurableTime() * 60 * 1000) {// 可以清除，先记录下来
                            tempSet.add(key);}}}// 真正清除Iterator tempIt = tempSet.iterator();while (tempIt.hasNext()) {Object key = tempIt.next();cacheMap.remove(key);cacheConfMap.remove(key);}System.out.println("now thread================>"+ cacheMap.size());// 休息try {Thread.sleep(60 * 1000L);} catch (InterruptedException e) {e.printStackTrace();}}}}}

package com.henu.util;/*** 缓存属性类* * @author Administrator* */
public class CacheConfModel implements java.io.Serializable {private long beginTime;// 缓存开始时间private boolean isForever = false;// 是否持久private int durableTime;// 持续时间public long getBeginTime() {return beginTime;}public void setBeginTime(long beginTime) {this.beginTime = beginTime;}public boolean isForever() {return isForever;}public void setForever(boolean isForever) {this.isForever = isForever;}public int getDurableTime() {return durableTime;}public void setDurableTime(int durableTime) {this.durableTime = durableTime;}}

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"><servlet><servlet-name>testCache</servlet-name><servlet-class>cache.com.Cservlet</servlet-class></servlet><servlet-mapping><servlet-name>testCache</servlet-name><url-pattern>/testCache.do</url-pattern></servlet-mapping><servlet><servlet-name>cacheinitservlet</servlet-name><servlet-class>cache.com.LoadCache</servlet-class><load-on-startup>2</load-on-startup></servlet><welcome-file-list><welcome-file>index.jsp</welcome-file></welcome-file-list>
</web-app>

package cache.com;import java.util.Date;
import javax.servlet.http.HttpServlet;import cache.com.CacheConfModel;
import cache.com.CacheMgr;
/*** 项目启动时默认加载缓存数据类* @author Administrator*/
public class LoadCache extends HttpServlet{public void init(){addData();}/*** 项目启动时加载缓存*/public void addData(){System.out.println("进入加载缓存addData()………………。");CacheMgr cm=CacheMgr.getInstance();CacheConfModel cModel=new CacheConfModel();Date d=new Date();cModel.setBeginTime(d.getTime());cModel.setDurableTime(60);cModel.setForever(true);cm.addCache("kk", "123", cModel);//在缓存加值
    }}

package cache.com;import java.io.PrintWriter;import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/*** 测试读取、添加缓存数据等* @author Administrator*/
public class Cservlet extends HttpServlet{public void service(HttpServletRequest request,HttpServletResponse response){try {System.out.println("进入servlet类............");request.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=UTF-8");   //3.设置响应类型
PrintWriter out = response.getWriter();CacheMgr cm=CacheMgr.getInstance();int numm=cm.getSize();//获取缓存个数Object ob=cm.getValue("kk");System.out.println("numm===========//======"+numm);out.println("缓存个数为："+numm);out.println("缓存数值：value===="+ob);} catch (Exception e) {e.printStackTrace();}}}

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'index.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--></head><body><form action="testCache.do" method="post"><button type="submit" >获取缓存数据</button></form></body>
</html>